In many systems, computers, input/output devices, storage devices, switches, etc. couple to each other across a backplane. Such devices install into slots in a cabinet in which the backplane is mounted. When installed in a slot, each device mates to a connector on the backplane. Because electrical connectivity between the various devices is implemented by the backplane, the backplane is designed to predict how users will install the various devices, which devices will be installed, etc.
Preferences as to the configuration of the system can be user-specific. For example, some users may prefer more storage devices than other users. The backplane design may, at least in part, dictate in which slots the user can install certain devices (e.g., servers, switches, storage devices, etc.). Any given backplane design may be acceptable to some users, but no doubt will not be acceptable to all users.